.NET/Java PDF, Tiff, Barcode SDK Library

It s tempting to put a simple JavaScript expression in the OnBegin handler or its counterparts, but this causes a syntax error in the generated onclick handler for the anchor tag. Make sure you reference the JavaScript function by name (without parentheses) like this: OnBegin = "ajaxStart".

However, this can sometimes seem like an overcomplicated solution in a lot of cases,.

ssrs qr code free, ssrs upc-a, barcode in vb.net 2005, ssrs gs1 128, ssrs ean 13, ssrs pdf 417, itextsharp remove text from pdf c#, itextsharp replace text in pdf c#, ssrs data matrix, c# remove text from pdf,

slow operations don t work synchronously under the covers Take fundamental operations such as reading and writing data from and to devices such as network cards or disks, for example The kernel-mode device drivers that manage disk and network I/O are instructed by the operating system to start doing some work, and the OS expects the driver to configure the hardware to perform the necessary work and then return control to the operating system almost immediately on the inside, Windows is built around the assumption that most slow work proceeds asynchronously, that there s no need for code to progress strictly in sync with the work This asynchronous model is not limited to the internals of Windows there are asynchronous public APIs.

There is no perfect number to the number of content types a web site should have I have seen awesome Drupal sites using only the default node types and also have been involved in projects where the site had more than 30 content types (note that I frequently use node type and content type interchangeably to refer to the same thing) Adding a content type is a matter of functionality and preference When I say functionality, I mean a few things First, does the node require one or more special fields In many cases, you will want to use the Basic Page content type for static pages while using another content type for, say, a project portfolio, catalog, or restaurant menu This additional content type has extra fields, such as image uploads and category tags, that differentiate it from a Basic Page.

These typically return very quickly, long before the work in question is complete, and you then use either a notification mechanism or polling to discover when the work is finished The exact details vary from one API to another, but these basic principles are universal Many synchronous APIs really are just some code that starts an asynchronous operation and then makes the thread sleep until the operation completes An asynchronous API sounds like a pretty good fit for what we need to build responsive interactive applications# So it seems somewhat ludicrous to create multiple threads in order to use synchronous APIs without losing responsiveness, when those synchronous APIs are just wrappers on top of intrinsically asynchronous underpinnings Rather than creating new threads, we may as well just use asynchronous APIs directly where they are available, cutting out the middle man NET defines two common patterns for asynchronous operations.

The Ajax link is just one of the helpers that invokes an action asynchronously. It s useful in scenarios where the logic is simple, such as notifying the server of an action or retrieving a simple value. For more complicated scenarios, where there s data to be sent to the server, an Ajax form is more appropriate. The Ajax form is created with an Ajax helper called Ajax.BeginForm. It behaves much like the Hijax technique discussed in section 12.3.2. Its usage is similar to the Ajax action link:

There s a low-level pattern which is powerful and corresponds efficiently to how Windows does things under the covers And then there s a slightly higher-level pattern which is less flexible but considerably simpler to use in GUI code..

The Asynchronous Programming Model (APM) is a pattern that many asynchronous APIs in the .NET Framework conform to. It defines common mechanisms for discovering when work is complete, for collecting the results of completed work, and for reporting errors that occurred during the asynchronous operation. APIs that use the APM offer pairs of methods, starting with Begin and End. For example, the Socket class in the System.Net.Sockets namespace offers numerous instances of this pattern: BeginAccept and EndAccept, BeginSend and EndSend, BeginConnect and EndConnect, and so on.

<% using(Ajax.BeginForm("AddComment", new AjaxOptions{ HttpMethod = "POST", UpdateTargetId = "comments", InsertionMode = InsertionMode.InsertAfter})) { %> <!-- form elements here --> <% } %>

#Asynchronous APIs tend to be used slightly differently in server-side code in web applications. There, they are most useful for when an application needs to communicate with multiple different external services to handle a single request.

The exact signature of the Begin method depends on what it does. For example, a socket s BeginConnect needs the address to which you d like to connect, whereas BeginReceive needs to know where you d like to put the data and how much you re ready to receive. But the APM requires all Begin methods to have the same final two parameters: the method must take an AsyncCallback delegate and an object. And it also requires the method to return an implementation of the IAsyncResult interface. Here s an example from the Dns class in System.Net: